Many nineteenth-century psychologists assume that the measurement of psychic intensity is a prerequisite to the development of a truly scientific psychology. In the first edition (1874) of the Psychology from an empirical point of view, Brentano deals with this question. He assumes that all psychic phenomena admit of a certain intensity. Later on, Brentano retreats this doctrine and claims that only sensible phenomena admit of an intensity, whereas intellectual presentations do not. As a consequence, Brentano introduces a radical gap between sensible and noetic consciousness. By contrast, Stumpf maintains a continuity between sensations and presentations. The main difference between them is the degree of their intensity. The essay provides a discussion and a comparison of the above mentioned points of view.
